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1.
Rev Argent Microbiol ; 55(3): 251-254, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37100682

RESUMO

Carbapenemase-producing-Serratia marcescens isolates, although infrequent, are considered important nosocomial pathogens due to their intrinsic resistance to polymyxins, which limits therapeutic options. We describe a nosocomial outbreak of SME-4-producing S. marcescens in Buenos Aires city which, in our knowledge, represents the first one in South America.


Assuntos
Infecção Hospitalar , Infecções por Serratia , Humanos , Serratia marcescens , beta-Lactamases , Infecções por Serratia/epidemiologia , Infecção Hospitalar/epidemiologia , América do Sul/epidemiologia , Surtos de Doenças
2.
Rev Argent Microbiol ; 53(3): 202-209, 2021.
Artigo em Espanhol | MEDLINE | ID: mdl-33402284

RESUMO

Actinomyces and related genera are grampositive bacilli, opportunistic pathogens, which have been mainly involved in endogenous infections. However, due to the complexity in identifying them for most clinical laboratories, there is scant knowledge about their real clinical significance. In this work, 166 isolates of 13 different species of Actinomyces/Actinotignum species recovered from clinical samples of patients treated in a university hospital were studied. The identification was performed by MALDI-TOF MS and molecular identification. MALDI-TOF MS identified 91.57% of the isolates (152/166) at the species level using a score ≥ 1.7 and 3.61% (6/166) of the isolates were identified only at the gender level with a score ≥ 1.5. MALDI-TOF MS did not yield reliable identification results for 4.82% (8/166) of the isolates. Actinomyces/Actinotignum species were isolated from: soft tissue (n: 47), urine samples (n: 35), head / neck abscesses (n: 19), genital abscesses (n: 11), blood samples (n: 10), breast abscesses (n: 8), osteoarticular samples (n: 6), abdominal/ascitic fluids (n: 3), abdominal abscesses (n: 5), sputum/BAL (n: 4), brain abscesses (n: 3), and others (n: 15). The results obtained from the statistical analysis showed a high differential frequency (> 2) for the location/species association: urine/A. schaalii/sanguinis; brain abscesses/A. europaeus; osteoarticular samples/A. urogenitalis; abdominal abscesses/ A. turicensis; respiratory samples/A. naeslundii/viscosus. This information provides a greater understanding of the clinical and epidemiological relevance of these species. The pathogenic role of Actinomyces spp. will be increasingly revealed as these microorganisms could be recognized thanks to prolonged culture and the advances in identification technology facilitated by MALDI-TOF MS.


Assuntos
Actinomyces , Actinomycetaceae , Hospitais , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
3.
Rev Argent Microbiol ; 52(2): 101-106, 2020.
Artigo em Espanhol | MEDLINE | ID: mdl-31628000

RESUMO

During the periods 2000-2004 and 2014-2015, Neisseria meningitidis was investigated in men who have sex with men, 1143 and 544 respectively, who consulted in the sexually-transmitted disease program. Prevalence, serogroup distribution and susceptibility to antibiotics were determined. Pharyngeal, rectal and urethral swabs were cultivated on selective Thayer-Martin modified medium. The identification was performed by biochemical tests and mass spectrometry by MALDI-TOF. Serogroups B, C, W and Y were investigated by PCR in 85 isolates recovered from the pharynx belonging to the second period. MICs of penicillin, ceftriaxone, rifampicin, azithromycin and ciprofloxacin were determined for 66 and 102 isolates from periods 1 and 2 respectively, according to CLSI. The prevalence of N. meningitidis was 17.8% and 28.1%, in periods 1 and 2 respectively; the isolates were mainly recovered from the pharynx. The distribution of serogroups was B 31.5%; Y 7.6%; W 3.3% and 9.8% non-capsulated and the rest would belong to other serogroups. Isolates classified as intermediate to penicillin were 34.8% and 63.7% (first and second periods, respectively); moreover, 11.8% of the isolates from the second period were resistant. All isolates were susceptible to ceftriaxone, to ciprofloxacin (except 3 isolates with MIC values between 0.25 and 0.5µg/ml), 3% were resistant to rifampicin and 2% were not susceptible to azithromicin. The prevalence of N. meningitidis carriage in men who have sex with men was high with a high rate of penicillin non-susceptible isolates. B was the prevalent serogroup.


Assuntos
Homossexualidade Masculina , Infecções Meningocócicas/microbiologia , Neisseria meningitidis/isolamento & purificação , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Humanos , Masculino , Infecções Meningocócicas/tratamento farmacológico , Infecções Meningocócicas/epidemiologia , Testes de Sensibilidade Microbiana , Neisseria meningitidis/classificação , Neisseria meningitidis/efeitos dos fármacos , Prevalência , Sorogrupo
4.
J Antimicrob Chemother ; 74(7): 1836-1841, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30993333

RESUMO

BACKGROUND: SME carbapenemases are increasingly reported, especially from North and South America. Here, we describe an SME-4-producing Serratia marcescens (SME-Sm) clinical isolate from Argentina and compare its genome with other SME-Sm and Sm isolates recovered from public databases. METHODS: Sm isolates were characterized by WGS using Illumina technology, susceptibility testing and MIC determination. Carbapenemase activity was revealed by biochemical tests based on imipenem hydrolysis. A whole-genome phylogeny was estimated for all the Sm isolates retrieved from public databases with kSNP3 and a whole-genome phylogenetic analysis based on non-recombinant core SNPs was inferred for Sm complete genomes and for those encoding any blaSME variants. RESULTS: Sm163 was resistant to amoxicillin, temocillin, aztreonam and carbapenems, remaining susceptible to extended-spectrum cephalosporins. WGS analysis of Sm163 revealed a genome of 5139329 bp and a chromosomally encoded blaSME-4 carbapenemase gene located on a genomic island closely related to SmarGI1-1 of Sm N11-02820. Comparison of the Sm genomes revealed that the 14 SME-Sm isolates possess this genomic island inserted at the same loci, that 13/14 belong to clade 1 and that 11/14 form a well-defined subcluster of cluster I of Sm clade 1, while Sm163 belongs to clade 2, suggesting that an SME-encoding genomic island may have been transferred between isolates from different clades. CONCLUSIONS: To the best of our knowledge this is the first report of an SME-4-encoding Sm from Argentina. The blaSME-4 gene is located on a SmarGI1-1-like genomic island. The genome of Sm163 belongs to clade 2, unlike all the other SME-Sm isolates, which belong to clade 1.


Assuntos
Proteínas de Bactérias/análise , Enterobacteriáceas Resistentes a Carbapenêmicos/classificação , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Genótipo , Infecções por Serratia/microbiologia , Serratia marcescens/classificação , Serratia marcescens/isolamento & purificação , beta-Lactamases/análise , Argentina , Enterobacteriáceas Resistentes a Carbapenêmicos/enzimologia , Biologia Computacional , Genoma Bacteriano , Ilhas Genômicas , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Filogenia , Serratia marcescens/enzimologia , Sequenciamento Completo do Genoma
5.
Rev Argent Microbiol ; 51(1): 26-31, 2019.
Artigo em Espanhol | MEDLINE | ID: mdl-29941157

RESUMO

Members of the viridans group streptococci (VGS) are the cause of local and invasive infections. Due to the severity of these infections and taking into account that reports regarding epidemiological aspects are scarce, the aims of this work were the identification and the study of the antibiotic susceptibility profiles of the isolates recovered from patients that were hospitalized in order to find out about the resistance level and the epidemiology of infections in which VGS are involved. A hundred and thirty two isolates identified as VGS were isolated at Hospital de Clínicas «José de San Martín¼ during the period 2011-2015. The identification was performed by biochemical test and mass spectrometry by Matrix Assisted Laser Desorption Ionization -Time of Flight Mass Spectrometry. Streptococcus anginosus group was prevalent (42%) followed by Streptococcus mitis group (33%). In the latter, isolates of Streptococcus pneumoniae were excluded. All the VGS isolates were susceptible to ertapenem, meropenem, linezolid and vancomycin; 25.8% were resistant (I+R) to penicillin, being prevalent in the S. mitis group. Regarding ceftriaxone and cefepime 96.9% of the isolates were susceptible. Only two isolates were resistant to levofloxacin, 27.2% to tetracycline and it was not found high level resistance to gentamycin (MIC range 0.5-32µg/ml). Resistance to erythromycin was 17.4% with no significant difference between M and MLS phenotypes. The most active antibiotics were in addition to ceftriaxone and cefepime, vancomycin, ertapenem, meropenem and linezolid. These results highlight the importance of the continuous surveillance of the infections caused by VGS in order to predict a correct antibiotic therapy.


Assuntos
Antibacterianos/farmacologia , Estreptococos Viridans/efeitos dos fármacos , Argentina , Farmacorresistência Bacteriana , Hospitalização , Hospitais de Ensino , Humanos , Testes de Sensibilidade Microbiana , Infecções Estreptocócicas/tratamento farmacológico , Infecções Estreptocócicas/microbiologia , Saúde da População Urbana , Estreptococos Viridans/isolamento & purificação
6.
Rev Argent Microbiol ; 51(2): 157-163, 2019.
Artigo em Espanhol | MEDLINE | ID: mdl-30541666

RESUMO

The etiology leading to neonatal damage is multifactorial, being genital infections one of the causes. The objective of the study was to identify microorganisms of the maternal genital tract that are associated with neonatal damage, in order to prevent future perinatal complications. Seven hundred and eleven pregnant patients attended their prenatal control during the period January 2010-July 2013. Ureaplasma urealyticum and Mycoplasma hominis presence was investigated in umbilical cord blood by metabolic substrates (Micofast-Biomerieux) and that of T.vaginalis, by PCR using specific primers. The microbiological study of the vaginal contents of 288 pregnant patients at weeks 35 to 37 was performed by conventional methods, adding the modified thioglycolate culture for T.vaginalis. GroupB streptococcus (GBS) was investigated in anorectal and vaginal introitus swabs, using selective broth enrichment and subsequent isolation in chromogenic medium. The χ2 Yates test and Fisher's test were used for independent samples. A p value <0.05 was considered statistically significant. The pathogens significantly related to neonatal damage were M.hominis (p=0.03), T.vaginalis (p=0.03), and BV (p=0.02). Main complications were preterm birth, premature rupture of membranes (PRM), low weight and Apgar score ≤7. U.urealyticum (p=0.35), Candidaspp. (p=0.94) and GBS (p=0.18) were not related to neonatal damage. Since different microorganisms of the maternal genital tract were related to neonatal damage, it is very important to perform the microbiological study of vaginal contents during pregnancy to prevent possible maternal and perinatal complications.


Assuntos
Sangue Fetal/microbiologia , Sangue Fetal/parasitologia , Doenças do Recém-Nascido/microbiologia , Mycoplasma hominis/isolamento & purificação , Complicações Infecciosas na Gravidez/microbiologia , Complicações Infecciosas na Gravidez/parasitologia , Trichomonas vaginalis/isolamento & purificação , Ureaplasma urealyticum/isolamento & purificação , Vagina/microbiologia , Vagina/parasitologia , Feminino , Humanos , Recém-Nascido , Gravidez , Estudos Prospectivos
7.
Rev Argent Microbiol ; 51(3): 247-250, 2019.
Artigo em Espanhol | MEDLINE | ID: mdl-30551810

RESUMO

One hundred sequential, epidemiologically unrelated carbapenem-resistant- Acinetobacter baumannii isolates from 11 hospitals in 10 Argentine provinces were collected between January and August 2016. Genes coding for Ambler class D and B carbapenemases were investigated by PCR using specific primers. All isolates were typed using the 3-locus sequence typing and blaOXA-51-like sequence-based typing techniques. The blaOXA-23 gene was recovered in all isolates studied. The population of carbapenem-resistant- A. baumannii in Argentina was principally associated with ST1 (45%), ST25 (34%) and ST79 (15%). ST25 was recovered in all the regions studied and CC2 was not detected.


Assuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/isolamento & purificação , Proteínas de Bactérias/genética , Carbapenêmicos/farmacologia , Infecção Hospitalar/microbiologia , Resistência beta-Lactâmica , beta-Lactamases/genética , Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/enzimologia , Acinetobacter baumannii/genética , Argentina/epidemiologia , Infecção Hospitalar/epidemiologia , Humanos
8.
Rev Argent Microbiol ; 50(3): 327-333, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29548732

RESUMO

Carbapenem resistance in gram-negative bacteria by production of carbapenemases is one of the most challenging issues regarding healthcare worldwide. We review the epidemiology and prevalence of carbapenemases in carbapenem-resistant Acinetobacter baumannii isolates from Latin American countries. High resistance rates to antimicrobial agents, particularly to carbapenems, are observed in this region. OXA-23 is the most widely disseminated class D-carbapenemase; it is present in all the countries of the region and is frequently associated to endemic clones CC113/CC79, CC104/CC15, CC110/ST25 and CC109/CC1. The emergence of OXA-72 and NDM-1 represents a novel finding which is observed simultaneously and without clonal relatedness in different countries, some of which are distant from one another, whereas OXA-143 is only present in Brazil. Further collaborative intraregional studies would provide a better understanding of these issues in most of the countries and thus, policies to control the spread of these isolates could be implemented.


Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Proteínas de Bactérias , beta-Lactamases , Acinetobacter baumannii/enzimologia , Acinetobacter baumannii/genética , Antibacterianos , Proteínas de Bactérias/metabolismo , Brasil , Humanos , América Latina , Testes de Sensibilidade Microbiana , Resistência beta-Lactâmica , beta-Lactamases/metabolismo
9.
Korean J Parasitol ; 54(2): 191-5, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27180578

RESUMO

The aim of this study was to evaluate different methods for Trichomonas vaginalis diagnosis during pregnancy in order to prevent maternal and perinatal complications. A total of 386 vaginal exudates from pregnant women were analyzed. T. vaginalis was investigated by 3 types of microscopic examinations direct wet mount with physiologic saline solution, prolonged May-Grunwald Giemsa (MGG) staining, and wet mount with sodium-acetate-formalin (SAF)/methylene blue method. PCR for 18S rRNA gene as well as culture in liquid medium were performed. The sensitivity and specificity of the microscopic examinations were evaluated considering the culture media positivity or the PCR techniques as gold standard. The frequency of T. vaginalis infection was 6.2% by culture and/or PCR, 5.2% by PCR, 4.7% by culture, 3.1% by SAF/methylene blue method and 2.8% by direct wet smear and prolonged MGG staining. The sensitivities were 83.3%, 75.0%, 50.0%, and 45.8% for PCR, culture, SAF/methylene blue method, and direct wet smear-prolonged MGG staining, respectively. The specificity was 100% for all the assessed methods. Microscopic examinations showed low sensitivity, mainly in asymptomatic pregnant patients. It is necessary to improve the detection of T. vaginalis using combined methods providing higher sensitivity, such as culture and PCR, mainly in asymptomatic pregnant patients, in order to prevent maternal and perinatal complications.


Assuntos
Reação em Cadeia da Polimerase/métodos , Coloração e Rotulagem/métodos , Vaginite por Trichomonas/diagnóstico , Trichomonas vaginalis/isolamento & purificação , Argentina , Amarelo de Eosina-(YS) , Feminino , Hospitais Universitários , Humanos , Azul de Metileno , Microscopia/métodos , Gravidez , Complicações Parasitárias na Gravidez/prevenção & controle , Sensibilidade e Especificidade , Vaginite por Trichomonas/parasitologia , Esfregaço Vaginal/métodos
10.
Rev Argent Microbiol ; 48(1): 57-61, 2016.
Artigo em Espanhol | MEDLINE | ID: mdl-26857425

RESUMO

In vitro activity of the combination of ampicillin- ceftriaxone against 30 Enterococcus faecalis isolates recovered from invasive infections in patients admitted to Hospital de Clínicas José de San Martin in the city of Buenos Aires was assessed. Ampicillin- ceftriaxone synergies were determined by microdilution in Müeller-Hinton (MH) broth with and without subinhibitory concentrations of ceftriaxone. Synergy was detected in 22/30 isolates. A decrease in both minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was observed in 14/30 isolates, whereas in 6/30 isolates the decrease was observed in the MIC value and only in the MBC value in the 2 remaining isolates. The bactericidal activity of the combination showed to be higher at low concentrations of ampicillin (< 1 µg/ml). We detected in vitro synergy using the ampicillin-ceftriaxone combination and thus, its efficacy was confirmed in the treatment of severe infections by E. faecalis.


Assuntos
Ampicilina/farmacologia , Ceftriaxona/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/isolamento & purificação , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Testes de Sensibilidade Microbiana
11.
Rev Argent Microbiol ; 46(4): 320-4, 2014.
Artigo em Espanhol | MEDLINE | ID: mdl-25576416

RESUMO

Two-hundred Acinetobacter isolates belonging to 200 patients admitted to Hospital de Clínicas José de San Martín during the period March 2013-June 2014 were analyzed. The identification was performed by mass spectrometry and was confirmed by molecular methods. Susceptibility to antimicrobials was studied by the Vitek-2 system. A 94% correlation of both identification methods was found. Multidrug resistant Acinetobacter baumannii was the predominant genomic species (92.6%) in hospital-acquired infections, whereas Acinetobacter pitti and Acinetobacter nosocomialis accounted for 3.5% and 0.5% of the isolates recovered, respectively. In community-acquired infections a major predominance of the different genomic species was observed. Acinetobacter johnsonii and A. baumannii are the most frequent species, accounting for 45.9% of the isolates recovered. Resistance to carbapenems and minocycline was only observed in A. baumannii. Mass spectrophotometry was an effective tool for the identification of the different genomic species.


Assuntos
Acinetobacter/efeitos dos fármacos , Acinetobacter/isolamento & purificação , Anti-Infecciosos/farmacologia , Argentina , Hospitais Universitários , Humanos , Testes de Sensibilidade Microbiana , Estudos Prospectivos , Saúde da População Urbana
12.
Rev Argent Microbiol ; 46(3): 210-7, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25444130

RESUMO

Resistance to ß-lactam/ß-lactamase inhibitors in enterobacteria is a growing problem that has not been intensively studied in Argentina. In the present work, 54/843 enterobacteria collected in a teaching hospital of Buenos Aires city were ampicillin-sulbactam-resistant isolates remaining susceptible to second- and third-generation cephalosporins. The enzymatic mechanisms present in the isolates, which were also amoxicillin-clavulanic acid (AMC)-resistant (18/54) were herein analyzed. Sequencing revealed two different variants of blaTEM-1, being blaTEM-1b the most frequently detected allelle (10 Escherichia coli, 3 Klebsiella pneumoniae, 2 Proteus mirabilis and 1 Raoultella terrigena) followed by blaTEM-1a (1 K. pneumoniae). Amoxicillin-clavulanate resistance seems to be mainly associated with TEM-1 overproduction (mostly in E. coli) or co-expressed with OXA-2-like and/or SHV ß-lactamases (K. pneumoniae and P. mirabilis). A new blaTEM variant (TEM-163) was described in an E. coli strain having an AMC MIC value of 16/8µg/ml. TEM-163 contains Arg275Gln and His289Leu amino acid substitutions. On the basis of the high specific activity and low IC50 for clavulanic acid observed, the resistance pattern seems to be due to overproduction of the new variant of broad spectrum ß-lactamase rather than to an inhibitor-resistant TEM (IRT)-like behavior.


Assuntos
Combinação Amoxicilina e Clavulanato de Potássio/farmacologia , Farmacorresistência Bacteriana/genética , Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/enzimologia , beta-Lactamases/isolamento & purificação , Substituição de Aminoácidos , Argentina/epidemiologia , Sequência de Bases , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , DNA Bacteriano/genética , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Infecções por Enterobacteriaceae/epidemiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/isolamento & purificação , Proteínas de Escherichia coli/metabolismo , Genes Bacterianos , Hospitais de Ensino , Hospitais Urbanos , Humanos , Dados de Sequência Molecular , Homologia de Sequência do Ácido Nucleico , Especificidade por Substrato , beta-Lactamases/genética , beta-Lactamases/metabolismo
13.
Rev Argent Microbiol ; 46(3): 182-7, 2014.
Artigo em Espanhol | MEDLINE | ID: mdl-25444125

RESUMO

Infections of the lower genital tract associated to maternal and perinatal complications frequently occur during pregnancy. The aim of this study was to evaluate vaginal dysfunction through the analysis of basic vaginal states (BVS) using the methodology of balance of the vaginal content (BAVACO) and to compare it with the microbiological study of candidiasis, trichomoniasis and bacterial vaginosis (BV). Pregnant patients (1238) were examined from 2010 to 2012. In asymptomatic (A) (n: 1046) and symptomatic pregnant women (S) (n: 192) BVS I was 59.5% and 26% of the patients, respectively. BVS II was observed in 19.7% of A and in 17.2% of S. BVS III was only detected in A in 0.4%. BVS IV was observed in 14.4% of A and in 38% of S. BVS V was detected in 6% of A and in 18.8% of S. Yeasts were associated to BVS I and II in 55.5% and 23.2% of A, respectively; and in 32.4% and 31% of S, respectively. Trichomonas were associated to BVS I in 50% of A, to IV in 44.4% of S and to V in 33.3% of S. BAVACO susceptibility to detect yeasts was 80.4% and 85.5% in A and S, respectively; 40% and 75% in A and S, respectively, to detect trichomonas and 100% in A and S to detect BV. BAVACO specificity was 100% for all pathogens in A and S. The study of BVS proved useful as a guide to evaluate vaginal dysfunction, regardless of symptomatology. Therefore, this study is recommended as prenatal control.


Assuntos
Candidíase Vulvovaginal/microbiologia , Complicações Infecciosas na Gravidez/microbiologia , Vaginite por Trichomonas/microbiologia , Vagina/microbiologia , Vaginose Bacteriana/microbiologia , Doenças Assintomáticas , Candidíase Vulvovaginal/epidemiologia , Feminino , Bactérias Gram-Negativas/isolamento & purificação , Humanos , Contagem de Leucócitos , Microbiota , Valor Preditivo dos Testes , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Estudos Prospectivos , Sensibilidade e Especificidade , Coloração e Rotulagem/métodos , Vaginite por Trichomonas/epidemiologia , Trichomonas vaginalis/isolamento & purificação , Vaginose Bacteriana/epidemiologia , Leveduras/isolamento & purificação
14.
Microb Drug Resist ; 30(3): 109-117, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38133499

RESUMO

Staphylococcus aureus bacteremia (SAB) is one of the most common serious bacterial infections worldwide. In this study, we demonstrated changes in SAB epidemiology in an Argentinean University Hospital during an 8-year period (2009-2016). A total of 326 S. aureus clinical isolates were recovered in three periods: P1: 2009-2010, P2: 2012-2014, and P3: 2015-2016. Among these, 127 were methicillin-resistant S. aureus (MRSA) and were characterized by phenotypic and molecular methods. We hereby report a significant decline in multiple drug resistance among MRSA isolates associated with an increase in SCCmec IV between the three periods. A diversity of MRSA-IV clones (mainly ST30-MRSA-IV, ST5-MRSA-IV, and ST8-MRSA-IV) replaced between 2009 and 2016 the previous prevalent MRSA clone causing bloodstream infections at this hospital (ST5-MRSA-I). MRSA population structure continued to diversify between P2 and P3. Notably, ST8-MRSA-IV-t008 related to USA300 was first detected during P2, and ST8-MRSA-IV together with ST30-MRSA-IV related to the Southwest Pacific clone were the more prevalent MRSA genotypes circulating during P3.


Assuntos
Bacteriemia , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Staphylococcus aureus/genética , Staphylococcus aureus Resistente à Meticilina/genética , Argentina/epidemiologia , Hemocultura , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Hospitais Universitários , Bacteriemia/tratamento farmacológico , Bacteriemia/epidemiologia
15.
Rev Argent Microbiol ; 45(3): 185-90, 2013.
Artigo em Espanhol | MEDLINE | ID: mdl-24165143

RESUMO

Sixty-four colistin-resistant Klebsiella pneumoniae isolates recovered from clinical specimens from 57 patients admitted to Hospital de Clinicas Jose de San Martin during the period 2010-2012 were studied to describe the microbiological and epidemiological characteristics and factors associated with the emergence of colistin-resistance. Fifty-four colistin-susceptible K. pneumoniae isolates from the same period were also included in the study. The genetic relatedness among the isolates was studied by a PCR assay. Fifty percent of the resistant isolates were KPC-2 producers, 45.3% were ESBL producers and 4.7% only showed resistance to aminopenicilins. All KPC-producers (resistant and susceptible to colistin) were genotipically indistinguishable except for one, whereas the presence of 7 clonal types, which were different from the ones identified in the colistin-susceptible isolates, were detected among ESBL producers. The previous use of colistin was the main factor associated with the acquisition of resistance, and in the case of non-KPC producers the stay in ICU was another significant factor observed. Colistin resistance emerged in our hospital in the year 2010, reaching 3% in nosocomial isolates and maintaining this rate in successive years, due to the selection of resistant subpopulations in the epidemic clonal type in KPC-producers and due to the dispersion of colistin-resistant clonal types in non-KPC producing-isolates.


Assuntos
Proteínas de Bactérias/biossíntese , Colistina/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , beta-Lactamases/biossíntese , Proteínas de Bactérias/classificação , Farmacorresistência Bacteriana , Feminino , Humanos , Infecções por Klebsiella/epidemiologia , Masculino , beta-Lactamases/classificação
16.
Antibiotics (Basel) ; 12(2)2023 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-36830286

RESUMO

Infections due to vancomycin-intermediate S. aureus (VISA) and heterogeneous VISA (hVISA) represent a serious concern due to their association with vancomycin treatment failure. However, the underlying molecular mechanism responsible for the hVISA/VISA phenotype is complex and not yet fully understood. We have previously characterized two ST100-MRSA-hVISA clinical isolates recovered before and after 40 days of vancomycin treatment (D1 and D2, respectively) and two in vitro VISA derivatives (D23C9 and D2P11), selected independently from D2 in the presence of vancomycin. This follow-up study was aimed at further characterizing these isogenic strains and obtaining their whole genome sequences to unravel changes associated with antibiotic resistance. It is interesting to note that none of these isogenic strains carry SNPs in the regulatory operons vraUTSR, walKR and/or graXRS. Nonetheless, genetic changes including SNPs, INDELs and IS256 genomic insertions/rearrangements were found both in in vivo and in vitro vancomycin-selected strains. Some were found in the downstream target genes of the aforementioned regulatory operons, which are involved in cell wall and phosphate metabolism, staphylococcal growth and biofilm formation. Some of the genetic changes reported herein have not been previously associated with vancomycin, daptomycin and/or oxacillin resistance in S. aureus.

17.
Microb Genom ; 9(5)2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37227244

RESUMO

Staphylococcus aureus remains one of the leading causes of infections worldwide and a common cause of bacteraemia. However, studies documenting the epidemiology of S. aureus in South America using genomics are scarce. We hereby report on the largest genomic epidemiology study to date of both methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) in South America, conducted by the StaphNET-SA network. We characterised 404 genomes recovered from a prospective observational study of S. aureus bacteraemia in 58 hospitals from Argentina, Bolivia, Brazil, Paraguay and Uruguay between April and October 2019. We show that a minority of S. aureus isolates are phenotypically multi-drug resistant (5.2%), but more than a quarter are resistant to macrolide-lincosamide-streptogramin B (MLSb). MSSA were more genetically diverse than MRSA. Lower rates of associated antimicrobial resistance in community-associated(CA)-MRSA versus hospital-associated (HA)-MRSA were found in association with three S. aureus genotypes dominating the MRSA population: CC30-MRSA-IVc-t019-lukS/F-PV+, CC5-MRSA-IV-t002-lukS/F-PV- and CC8-MRSA-IVc-t008-lukS/F-PV+-COMER+. These are historically from a CA origin, carry on average fewer antimicrobial resistance determinants, and often lack key virulence genes. Surprisingly, CC398-MSSA-t1451-lukS/F-PV- related to the CC398 human-associated lineage is widely disseminated throughout the region, and is described here for the first time as the most prevalent MSSA lineage in South America. Moreover, CC398 strains carrying ermT (largely responsible for the MLSb resistance rates of MSSA strains: inducible iMLSb phenotype) and sh_fabI (related to triclosan resistance) were recovered from both CA and HA origin. The frequency of MRSA and MSSA lineages differed between countries but the most prevalent S. aureus genotypes are high-risk clones widely distributed in the South American region without a clear country-specific phylogeographical structure. Therefore, our findings underline the need for continuous genomic surveillance by regional networks such as StaphNET-SA. This article contains data hosted by Microreact.


Assuntos
Bacteriemia , Staphylococcus aureus Resistente à Meticilina , Sepse , Infecções Estafilocócicas , Humanos , Staphylococcus aureus/genética , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus Resistente à Meticilina/genética , Bacteriemia/epidemiologia , Genômica , Brasil
18.
J Clin Microbiol ; 50(3): 1086-8, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22205811

RESUMO

Bifidobacterium species are difficult to identify and may be underreported or not recovered by many laboratories because of their slow growth. We emphasize the importance of the Gram stain in urine samples and the addition of enriched media and enhanced atmosphere over time for urine cultures with pyuria. This is the first report of a Bifidobacterium scardovii recurrent urinary infection in an elderly woman.


Assuntos
Infecções por Bifidobacteriales/diagnóstico , Infecções por Bifidobacteriales/patologia , Bifidobacterium/classificação , Bifidobacterium/isolamento & purificação , Idoso de 80 Anos ou mais , Técnicas de Tipagem Bacteriana , Técnicas Bacteriológicas/métodos , Infecções por Bifidobacteriales/microbiologia , Bifidobacterium/genética , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Feminino , Violeta Genciana , Humanos , Dados de Sequência Molecular , Fenazinas , Filogenia , Piúria/diagnóstico , Piúria/microbiologia , Piúria/patologia , RNA Ribossômico 16S/genética , Recidiva , Análise de Sequência de DNA , Urina/microbiologia
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